The point of --disable-bootstrap is to disable bootstrapping.
Why would somebody ever want to *disable* it? If you don't want to
bootstrap, you just don't *do* it!
The most important of these is libgcc and the crt startup files, which
currently do live in the gcc directory, and folks have wanted to move
out of it for five or ten years. We can't skip them during a
bootstrap; it just won't work.
Why is it so important to move them out? It would seem to me that the
bootstrap issue is a good reason *not* to!
So we define the GCC directory as containing precisely those things that
are *needed* for a bootstrap and those things outside are things that we
might also *want* to bootstrap.
